On Thursday, President Obama will award the Medal of Honor to Cpl. Kyle Carpenter, making him the 15th recipient of the nation's highest military award for bravery after more than a decade of war in Iraq and Afghanistan.

The medal is a remarkable honor, and while it is a symbol of courage and sacrifice for those who receive it, it's not something many aspire to.

That's because the criteria for receiving the award is incredibly stringent, requiring significant risk to life and limb in direct combat and a display of "personal bravery or self-sacrifice so extraordinary as to set the individual apart from his or her comrades."

For some service members put into extreme circumstances, the daily grind can give way to moments of incredible bravery that warrants them the nation's highest award.

Often it is the family of the fallen hero who receives the posthumous award. In the wars in Iraq and Afghanistan, there have been relatively few who have received the honor after more than a decade of combat.

Sergeant First Class Paul Smith held off hundreds of Iraqi soldiers from an exposed position.

On April 4, 2003, after his unit briefly battled and captured several Iraqi fighters near the Baghdad International Airport, Smith instructed his men to build an impromptu holding area for the prisoners in a nearby walled compound.

A short time later, his troops were violently attacked by a larger force. Smith rallied his men to organize a hasty defense, then braved hostile fire to engage the enemy with grenades and antitank weapons.

He then ran through blistering gunfire to man the .50 caliber machine gun on top of an armored personnel carrier to keep the enemy from overrunning the position, completely disregarding his own safety to protect his soldiers.

Smith was mortally wounded during the attack, but he helped defeat the attacking force which had more than 50 enemy soldiers killed, according to his award citation.

Corporal Jason Dunham dove on an enemy grenade and saved the lives of two Marines.

While his unit was engaged in a major firefight in Iraq along the Syrian border on April 14, 2004, Dunham and his team stopped several vehicles to search them for weapons.

As he approached one of the vehicles, the driver lunged at Dunham's throat and they fought in a hand-to-hand battle. Wrestling on the ground, Dunham then yelled to his Marines, "No, no watch his hand."

The insurgent then dropped a grenade with the pin pulled. Dunham jumped on top of it, placing his helmet between his body and the grenade in an effort to brunt the explosion.

"He knew what he was doing," Lance Cpl. Jason A. Sanders, who was in Dunham's company, told Marine Corps News. "He wanted to save Marines' lives from that grenade."

He saved the lives of at least two Marines and was mortally wounded in the blast.

Lieutenant Michael Murphy went into the open during a fierce battle to call for support.

While leading his Navy SEAL team on June 28, 2005, to infiltrate and provide reconnaissance on a Taliban leader, Murphy and the three other members of his team came under withering gunfire from 30 to 40 enemy fighters.

The fierce gunfight pitted the SEALs against insurgents on the high ground, and they desperately called for support as all four operators were hit by gunshots.

When his radioman fell mortally wounded, and with the radio not able to get a clear signal, Murphy disregarded the enemy fire and went out into the open to transmit back to his base and call for support.

From his Summary of Action:

He calmly provided his unit’s location and the size of the enemy force while requesting immediate support for his team. At one point he was shot in the back causing him to drop the transmitter. Murphy picked it back up, completed the call and continued firing at the enemy who was closing in.

"I was cursing at him from where I was," Hospital Corpsman Marcus Luttrell, the only survivor of the battle, later told The New York Times. "I was saying, 'What are you doing?' Then I realized that he was making a call. But then he started getting hit. He finished the call, picked up his rifle and started fighting again. But he was overrun."